Apparatus for controlling rotation



Supt. 3, 1946.

A. SATTERLE E 2,406,855

APPARATUS FOR CONTROLLING ROTATION Filed March 2, 1936 3 Sheets-Sheet 1 INVENTOR.

BY HOWARD A; SATTERLEE FIG. '3

, Sept. 3, 1946- H. A. SATTERLEE APPARATUS FOR CONTROLLING ROTATION Filed March 2, 1936 s Sheets-Sheet 2 $2 49 FIG. 4

25c. su bLv POTENTIAL FIG. 5

INVENTOR. HQWARD'AS T'FERLEE Wick? P 1946- H. A..SATTERLEE I 65 APPARATUS FOR CONTROLLING ROTATION Filed March 2, 1936 3'Sheets-Sheet 3 I ea A I 77 76 14, C. SUDPLY 0.901 DELAY 7' 6/ e2 EX? E Y FIG; 6

, 'INVENTOR'. HowARo A. SATTERLEE Patented Sept. 3, 1946 UNITED STATES PATENT OFFICE APPARATUS FOR CONTROLLING ROTATION Application March 2, 1936, Serial No. 66,634

6 Claims. 1

The present invention relates to an apparatus for controlling rotation. More particularly the present invention relates to an apparatus for rotating a heavy device into a desired position from a remote point.

The present invention is especially adaptable to the control of the rotation of a signaling head on a ship. In signaling under water with compressional Waves it is often desirable to project a signaling head through the skin of the ship into the water beneath. The signaling head i a device for sending or receiving compressional waves. In many cases it is necessary to be able to rotate the signaling head into various positions. This is particularly necessary when the signaling device has a strong directional characteristic such asis the case with a compressional wave transmitter or receiver whose diaphragm is large in comparison with the wave length employed. For this purpose it is necessary to be able to rotate the signaling head into any desired position with considerable accuracy.

Heretofore the most accurate way of accomplishing this has been by means of a hydraulic control arrangement. However, hydraulic devices are extremely expensive and a cheaper control system is very much desired. Electric motordriven arrangements have also been used, but these have been open to a number of objections. They have not permitted a sumciently accurate and close setting of the signaling device and have been rather erratic in behavior in that it has not been possible to obtain a smooth flow of power to rotate the signaling device. Furthermore, it has not been possible at a reasonable cost toobtain a variable operating speed with full torque at low starting speed or variable speed with full torque.

According to the present invention there is provided an improved electrical system for controlling the rotation and position of a signaling head; and for controlling the motion and position of any massive device. such as, for instance, a gun or a bridge or the like. Furthermore, the present invention provides a variable peed device with full torque available at all speeds.

The present invention will best be understood from the following description with. reference to the accompanying drawings in which Fig. l is a schematic representation of the mechanical elements of the system; Fig. 2 is an elevation of an adjustable resistance device which is hown partly in section in Fig. 1 and is employed in the modification shown in Fig. 4; Fig. 3 is an elevaschematic wiring diagram of one modification of the invention; Fig. 5 shows certain voltage curves illustrating the operation of the system shown in Fig. 4; Fig. 6 shows a modification of the invention; and Fig. 7 shows an elevation of an adjustable resistance device employed in the modification shown in Fig. 6.

The signaling head is shown at in Fig. 1 mounted at the end of the tube 2 projected through the skin 3 of the ship. At the upper end of the tube 2 is a shaft 4 to which are rigidly secured the gears 5 and B. The actual work of rotating the head I is accomplished by the motor I to which further reference 'will be made later. At some convenient place in the Vessel, for exampic, on the bridge or in the radio room, there is mounted a handwheel 8 at the end of a shaft 9. A gear I0 i fixed to the shaft 9 and meshes with a gear H fixed to the shaft l2. Also fixed to the shaft I2 i a dial E3 the front view of which is shown in Fig. 3. Also fixed to the shaft 9 is a gear [4 which meshes with gear I5 fixed to shaft l6 which carries an inertia mass I! to prevent too rapid a turning of the handwheel B. At the end of shaft 9 there is fixed a gear l8 forming part of a difierential system which includes also the idler gear I9 and the gear 29. The idler gear carrier I9 i fixed to the end of shaft 2| 'while the gears 2i! and 39 are fastened to each other, but

free to revolve on the shaft 2|. At the opposite end of shaft 2! there is mounted a cam 22 carrying the arms 23, 24, whose ends are provided with rollers 25 and 26, respectively, adapted to make contact with resistance windings 21 and 23 tion of the control Wheel and scale; Fig. 4 is a wound around an insulating ring 29 fixed to the support 29a.

An elevation of this variable resistance device is shown in Fig. 2 from which it will be noted that each of the resistances 21 and 28 are circular in shape and extend over approximately ninety degrees of arc. Furthermore, it will be noted that they are so arranged that the roller 25 can make contact only with the resistance 2'! and that roller 26 can make contact only with resistance 28. stops 30, 3! and 32 being provided on the support 29c and on the arms 23 and 24 to limit the rotation of these arms. It will also be noted that the resistances are arranged so that only one of the rollers is in contact with its resistance at a time. Thus, as shown in Fig. 2, while the roller 25 is in contact with the resistance 21, the roller 26 is bearing against the insulating ring 29. This variable resistance serves to control the operation of the gaseous electron tubes 33, 3t, shown in Fig. i, as will be described later.

As mentioned above, a gear 5 is rigidly fixed to the signaling head shaft 2 and rotates with it. Meshing with the gear 5 is a gear 35 which is fixed to the shaft of a self-synchronous generator 35. The ratio of gear 5 to gear 35 is the same as that between gears H and Ill, respectively. The self-synchronous generator 36 drives the self synchronous motor 31 which, through gears 33 and 39 of a one to one ratio, rotates the arms 23 and 24.

The operation of the mechanical parts of the system just described is briefly as follows: When the handwheel 8 is turned to set the dial l3 to the desired bearing of the signaling head, the arms 23 and 24 are rotated to cause one of the rollers to make contact with its resistance, thereby operating one of the gaseous electron tubes 33 or 34 and causing the motor I to rotate in the proper direction. The rotation of the signaling head by the motor also rotates the self-synchronous generator 36 which reacts upon the motor 3'! which, in turn, tends to turn the arms 23 and 24 back to their original position which will. be reached when the signaling head I faces in the direction indicated by the setting of the dial [3.

The operation of the motor 1 and its control will be evident from a consideration of Fig. 4. The motor 7 is of the type generally used as a direct current shunt motor. It has an armature 40 and a field winding 4| which, however, is separately excited from a source of direct current. Its armature 40 is in series with a source of alternating current and with the anode-cathode circuit of either of the electron tubes 33 or 34 depending upon the position of the relay 42. The tubes 33 and 34 are three-electrode electron tubes of the gaseous type.

When the moving arm 43 of the relay connects with contact 44 as shown in Figure 4, the armature 40 is in series with the anode of the tube 33, while when the relay coil 42 is deenergized, its moving arm 43 will be in connection with contact 45, thereby placing the armature 40 in series with the anode of tube 34. It will be noted that when 43 contacts 44, current impulses will flow through the armature 40 in one direction while when 43 contacts 45, current impulses will flow through the armature in the opposite direction. The coil 42 of the relay is energized when the contacts 46, 41 are closed by the cam 22. This occurs when the arm 23 makes contact with resistance 2! whereas the contacts 46, 51 are open when the arm 24 makes contact with the resist ance 23.

The cathodes of the tubes 33 and 34 are supplied with energy from the alternating current source through a transformer having a primary winding 48 and two secondary windings 49 and 50, the cathode of tube 33 being supplied from the secondary winding 49 while the cathode of tube 34 is supplied from the secondary winding 50. The anode circuit of tube 33 is returned to its cathode by means of the conductor 5| which is connected to a center tap on the secondary winding 49. Likewise the anode circuit of the tube 34 is returned to its cathode by means of the conductor 52 which is connected to a center tap on the secondary winding 50.

The grid cathode circuits of the tubes 33 and 34 are energized through the transformer 53 which is supplied from the same source of alternating current as the anode circuits. The transformer 53 has a primary winding 54 and two secondary windings 55 and 56, each of the latter being provided with a center tap. The grid cathode circuit of the tube 33 also contains a currentlimiting resistor 57 and a choke 58 in series with the secondary 55. Likewise, the grid cathode circuit of the tube 34 contains the current-limiting resistor 59 and the choke 60 in series with the secondary winding 56. These elements t0- gether with the resistances 21 and 28, which are introduced into the circuit by the operation of the arms 23 and 24, form phase-shifting networks for varying the phase of the grid--cathode volt age with respect to the anode-cathode voltage of each of the two tubes 33 and 34. As is known, by varying the relative phase between the grid and anode voltages, it is possible to vary the length of time in each cycle during which the discharge tube is conductive whereby the average anode current is varied.

It has been customary, however, to bring about the phase shift of grid voltage progressively in the opposite direction from that of the passage of time as determined by the anode potential, whereas in the present invention the progressive phase shift occurs in the same direction as the passage of time. Also, in the present arrangement the anode circuits contain the armature of the shunt motor I. When the armature revolves, a back E. M. F. will be developed in its windings which will oppose the applied alternating voltage during one-half of the cycle and will aid it during the other half of the cycle. Furthermore, the back E. M. F. will oppose the alternating voltage during that portion of the cycle in which one of the discharge tubes is conductive and during which current flows through the armature. This has the effect of limiting the maximum speed at which the motor 4|] will run with any given setting of the variable resistance device.

All this will better be understood by a con sideration of Fig. 5 in which various voltages are plotted as ordinates against time as abscissae. If we assume that the arms 23 and 24 of the variable resistance are in such a position that they both contact only the insulating ring 2 which would be in a vertical position in Fig. 4, the alternating potential applied tothe grid of each tube will be degrees out of phase with the anode potential of that tube as indicated by the curve E91. The anode voltage is illustrated by the curve E19. Since in order for either tube to discharge, it is necessary that the grid voltage be above a certain minimum, which we may assume for the purpose of this discussion to be zero volts, it will be evident that neither tube can discharge under these conditions, and consequently the motor I will remain at rest.

If, now, the handwheel be turned so that one of the arms makes contact with its resistance, say, as shown in Fig. 4, so that the arm 23 makes contact with resistance 21, the contacts 46 and 47 will be closed by the cam 22 and consequently the relay coil 42 will be energized closing con-- tacts 43 and 44 and opening the anode circuit to the tube 34. Under suitable conditions, tube 33 can then operate, while tube 34 is isolated from the circuit. The alternating potential which is now applied to the grid f tube 33 is less than 180 degrees out of phase with the anode potential of that tube as indicated, for example, by the dotted curve Egg. Let us assume that the minimum anode potential required to effect a discharge of the tube is the value a, as indicated by the line Ep(minimum). It will now be seen that in a positive half cycle of anode voltage, as indicated by the curve Ep, when the anode Voltage reaches the value a, the grid voltage Egg is still positive. At this point, therefore, the discharge will take place and anode current will flow through the armature 40 to the end of the positive half cycle when the anode voltage again becomes negative. In the latter condition the tube cannot, of course, conduct current since it is a uni-directional device, but in the succeeding positive half cycle, the same effect will again our. The armature 40 will, therefore, be energized with uni-directional current impulses causing it to rotate.

As the armature gains in speed, a back E. M. F. will be generated. Now. it will be noted from Fig. that at the instant the anode voltage reaches the value b, the grid voltage Egz has reached zero. Therefore, the back E. M. F. can increase until it has the Value (b-a), for if it becomes greater than this, no further current impulses will be supplied to the motor armature, wherefor its speed will decrease. This is because a back E. M. F. of the value (ba) is sufiicient to reduce the anode voltage to its minimum permissible value at the instant the grid voltage reaches its minimum value so that no discharge of the tube occurs. If, now, the arm 23 were turned still further in a clockwise direction, the grid voltage curve Egz would be displaced still more to the right in 5 and consequently the back E. M. F, and therefore also the speed of the motor could build up to a higher value than previously.

It should be noted that the progressive phase shift of grid voltage with respect to anode voltage in starting the motor is in the same direction as the passage of time as determined by the anode voltage, as shown in Fig. 5. This i made possible by choosing the correct polarity for the primary of transformer 53, and results in the ap plication to the motor of maximum power. The motor consequently develops maximum torque on starting.

From the above it will be evident that the tube 33 with the phase shift control of its grid voltage in combination with the shunt motor 1 offers an arrangement for obtaining a variable motor speed with full torque at starting which obviously may be useful in a number of instances other than the example herein given. It is particularly useful where the inertia of a heavy mass must be overcome in order to set it in motion.

Referring again to Fig. 4 it will be evident that when the arm 24 makes contact with the resistance 28, the contacts 46, 41 will be opened and contacts 43, 45 closed, whereby the tube 34 becomes active to rotate the armature Ml in the reverse direction from before. The control of the potential of the grid of tube 34 is similar to that described with reference to tube 33 and th back E. M, F. generated in the armature of the motor I likewise brings about an automatic limitation of the motor speed. The system as de'- scribed, therefore, not only provides a 'motor speed control, but also provides this control for both directions of rotation.

In the system as applied to the rotation of the signaling head shown in Fig. 1, it will now be understood that when the handwheel has been rotated to set the dial 13 in a given position which may result, for example, in setting the arm 23 on the resistance 21, as shown in Fig. l, the motor 1 will operate to rotate the signaling head I into the desired direction. At the same time,

- however, the self-synchronous generator 36 is being rotated and is effecting a rotation of the self-synchronous motor 31, whereby the arm 23 is again moved back to its original position, making contact with the insulating ring 29, at which time the grid voltage of tube 33 will again be exactly degrees out of phase with its anode voltage so that current can no longer flow, through the motor armature which consequently will cease turning.

Should the inertia of the parts be such that the motor revolves the signaling head 1 beyond the desired position, the self-synchronous motor 31 will likewise rotate the arms 24 beyond the insulating segment 29 so that the arm 24 makes contact with the resistance 7.8 and also causing the contacts 46, 4'! to open and thereby to deenergize the relay 42 which permits contacts 43, 45 to close. The tube 34 is, therefore, energized to rotate the motor in the reverse direction to bring the signaling head back into the desired position.

It should be noted that the resistance 21 (or 28) is varied from an infinite to a finite value at the very first turning of the handwheel from its position of rest. Upon continued turning of the handwheel, the resistance is finally gradually reduced to zero. Now, since maximum torque is developed by the motor while the resistance is near its maximum finite value, as explained above, it is highly desirable to place a limitation upon the speed with which the handwheel is turned so as to give the motor time to set the signaling head into rotation while maximum torque is still available. This is the function of the inertia weight I1, shown in Figure 1, although any other suitable device may be substituted for limiting the speed at which the handwheel 8 can be turned, particularly at starting.

On the other hand, the resistances can be ta pered or arranged in steps of any desired magnitude in order to obtain any desired speed at the various settings of the resistance control arm. It may, for example, be desired to have the motor rotate extremely slowly near the position of balance and when the handwheel is only very slightly displaced while much faster rotation is to occur when the handwheel is displaced a greater amount. For this purpose the resistance variation is made small near the position of balance and is made to reduce rapidly for greater displacements of the resistance arm.

The handwheel 8 need, of course, not be manually operated, but it can be controlled by an automatic device, such as, for example, a gyro-- compass in order to keep the device I facing in a desired direction.

The system shown in Figs. 6 and '7 is in many ways superior to the arrangement shown in Fig. 4. The modified arrangement is considerably simpler in as much as one of the transformers and the chokes are eliminated. Furthermore, a very smooth control of the'signaling head or of speed variation can be obtained.

In Fig. 6 the motor 1 is likewise of the direct current shunt motor type having its field winding 52 separately excited from a direct-current source. The gaseous electron tube 63 has its anode-cathode circuit supplied with alternating current and contains the armature 6! of the motor l in series with it. A relay 65 is provided which is a double-pole, double-throw relay and serves to reverse the connections of the arma ture SI of the motor I. The potential applied to the grid of the tube 63 is obtained from the direct current source through the current-limiting resistor 64 and the variable potentiometer resistance 66. This resistance may be uniform or tapered or stepped as mentioned above with respect to the resistances .27 and 28 of Fig. i.

A. convenient mechanical form of the latter is shown in Figure 7. This variable resistance is mounted on the shaft 2! in Figure 1 in place of the device there shown and described in connection with Figure 4. The contact arm 61 normally makes contact with a conducting segment 68 mounted upon a suitable disc of insulating material 59. On either side of the segment 68 are the resistances "ill and "H with which the arm 6'! makes contact when it is moved to one side or the other of segment A cam 72 is also provided fixed to the shaft 2! so that it rotates with the arm 67. The cam i3. s arranged so that the contacts l3, W are open when the arm t l engages the segment 63 as well as while it engages the resistance ll. On the other hand, the contacts 73, M are closed while the arm 6'! engages the resistance Hi. When the contacts 13, M are closed, the coil "E5 of the relay is energized from the direct current supply, thereby connecting the armature ii! in the anode-cathode circuit of the tube in one direction; but when contacts l3, l4 open, the relay coil is doenergized and the armature is connected in the anode circuit in the reverse direction. Since current always flows through the anode circuit in the same direction, the motor armature will rotate in one direction the other, depending upon whether the arm s contact with the resistance Hi Or with the s'istancc H.

The outer ends of the resistances Hi and H are connected to the source of direct current while the inner ends, nav ely those adjacent to the segment 68, are connected together and through a high resistance to the segment lit and thence through. the resistance l'li to the cathode of tube The gr'l cathode circuit of the tube thus traced from the id of the tube through resistance 34 to the in Ell. Then when the arm in contact with segment the circuit continues through resistances "ll and iii to the cathode, and when the is in contact with the resistances is or ll, the circuit continues through a portion of the respective resistance to the resistance Ill and the cathode of the tube. It will be noted that the resistances "ill and H are each potentiometers connected across a source of (iireel: current, their outer terminals being positive and their inner terminals negative. Thus, as the i G? is moved outward, away from the segment along either of the resistances N or H, the d of tube E3 becomes more and more positive with res ect to the cathode.

[is soon as the grid of tube 63 becomes positive, the tube will become conductive and uni-directic-pal, current impulses will flow in the anode circuit through the armature 6| causing it to lotate. The rotation of the armature in the direct current field produced by the winding 62 causes a back E. M. F. to be induced in the armature winding. The armature, it will be noted, is connected through the conductors l8 and Til across the terminals of the resistance l6 which is in the grid cathode circuit as above described. The back E. M. F. is thus impressed across this resist ance and is in the opposite direction to the grid cathode potential supplied through the resistance ill or H. As the armature El speeds up un der the influence of the anode current, the back M. F. builds up to a greater and greater value until it is sufiiciently high to neutralize the grid potential supplied through the resistances l0 and "H and thereby cause the grid potential to fall below the critical potential and consequently to cut off conduction through the tube. Thereupon the armature ill, no longer being supplied with current impulses, tends to slow down and the back E. M. F. consequently decreases to a point where it is no longer sufficient to neutralize the applied positive grid potential whereupon the tube again becomes conductive. This phenomenon is repeated and results in the armature attaining a constant speed determined by the setting of the arm ll'l along the resistance Ill or II. It will be evident that not only at starting but also at all speeds full torque is available, the armature being supplied with current impulses just sufficient in number to keep its speed at the value determined by the setting of the resistance 66 and the back E. M. F. developed by the armature.

As applied to the rotation of the signaling head, it has already been mentioned that the arm 61 is to be fixed to the shaft 2| of Figure 1. Thus, when the handwheel 8 is displaced in order to change the position of the signaling device I, the arms 5'! will be moved onto one or the other of the resistances Ill, H and will be moved along the resistance by an amount depending upon the amount of change of position which is desired as indicated on the dial coupled to the handwheel 8. The subsequent rotation of the motor l in turning the signaling device into the desired position also brings about the rotation of the se1f-synchronous gene ator 35 and the self-synchronous motor 31, ch through gears 38 and 39 operates to return the arm. E5 toward the segment 68 which will be reached when the signaling device has been rotated into the proper position. When this position is reached, the motor stops.

Since the motor speed is dependent upon the position of the arm 67 on the resistance It! or "H as explained above, it will be understood that as the signaling device approaches the desired position and consequently as the arm fil approaches the segment 58, the motor speed grad ually reduces, so that the signaling device comes to a smooth stop. There is substantially no teudency for it to overshoot the desired position, although if it should do so, the motor will reverse at slow speed to return to the correct posi-- tion. Extremely accurate settings can be made with the added advantages of high speed for large position changes, low speed for small changes, full torque at all speeds; and at the same time the apparatus required is simple, sulting in low manufacturing and maintenance costs.

The arrangement shown in Figure 4 employs two tubes, but it is evident that one of these be dispensed with by replacing the relay $2 with a double-pole, double-throw relay arranged in a manner similar to that shown in Figure 6.

While my invention has been described chiefly as applied to a system for moving a body into desired position, it has been mentioned that my invention also provides a variable speed d system. As such, it can readily be app] to the operation of machines at desired variable speeds. In this case it will be understood. of course, that the coupling between the moved device and the resistance device represented in Figure 1 by the self-synchronous machines and ill and the attendant gearing can be ornitted. It will also be evident that any desired sequence of fast or slow operation can readily be obtained by suitably proportioning the steps into which the resistance means are divided and the manner in which the contacting arm is moved over them.

Having now described my invention, I claim:

1. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination with said signaling head, a shaft on which said signaling head is mounted, an electric motor for rotating said shaft and means for controlling the operation of said motor including a differentially controlled rotary system having means for controlling the speed and direction of rotation of said motor, said means having a point of stationary balance, means adapted to be rotate-d in one direction to rotate said shaft and signaling head clockwise and adapted to be rotated in a reverse direction to rotate said shaft counterclockwise, and a follow-up device operative through said rotary system to bring said means for controlling the speed and direction of rotation of said motor to said point of stationary balance for each operation of positioning said signaling head.

2. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination with said signaling head, a shaft for turning the same, an electric motor for rotating said shaft. means for controlling the operation of said motor and the position of the signaling head including a control switch for starting and stopping said motor and controlling the direction of rotation thereof and differential rotary means for oper ating said control switch, said means having means manually operative to turn the control switch a desired amount in one direction and also having means operating through the signaling head shaft to return the control switch the de sired amount advanced.

3. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination With said signaling head, a shaft for turning the same, an electric motor for operating said shaft, a control switch means for starting and. stopping said motor and controlling the direction of rotation thereof and a differential system operating said control switch means, said system including meansfor manually turning said control switch in either direction, and means for returning the control switch to its normal position, said last means including means operatively associated with the signaling head shaft.

4. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination with said signaling head, a shaft for turning the same, an electric motor for rotating said shaft, a control switch means for starting and stopping said motor and controlling the direction of rotation thereof and a differential system operating said control switch means, said system including means for manually turning said control switch in either direction, means for returning the control switch to its normal position, said means including means operatively associated with the signaling head shaft, said control switch including means for applying direct current impulses to said motor, the direction of said impulses controlling the direction of rotation of the motor.

5. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination with said signaling head, a shaft for turning the same, an electric motor for rotating said shaft, 2. control switch means for starting and stopping said motor and controlling the direction of rotation thereof and a differential system operating said control switch means, said system including means for manually turning said control switch in either direction, means for returning the control switch to its normal position, said means including means operatively associated with the signaling head shaft, said control switch including means for applying direct current impulses to said motor to rotate the motor in the direction desired.

6. In a submarine signaling system having a signaling head, means for controlling the position of said signaling head including in combination with said signaling head a shaft on which said signaling head is mounted, an electric motor for rotating said shaft, means for controlling the operation of said motor including means having a neutral position but adapted to be rotated in one direction to operate said motor for rotation of said signaling head clockwise and adapted to be rotated in a reverse direction to operate said motor for rotation of said signaling head counter-clockwise, said means including a follow-up device operatively associated with the rotation of said signaling head to cause said rotatable means to be returned to its normal neutral position.

HOWARD A. SATTERLEE. 

